The visa is the document that entitles you to enter the country.  Upon arrival in Belgium, you will have to apply for a residence permit or declaration of presence at the local government office in your place of residence.

More guidelines on Covid-19 measures for incoming students and staff travelling to Belgium can be found on the website of the university.

EEA+ nationals

EU, Norway, Iceland, Liechtenstein, Monaco and Switzerland

Non EEA+ nationals